Generally, a vehicular electronic control apparatus (ECU) includes a non-volatile memory. The vehicular electronic control apparatus manages market specifications, for example, market specifications for North America by storing information corresponding to the destination in the non-volatile memory during a manufacturing of the vehicle. Herein, destination indicates a transportation destination or an exportation destination for selling out the vehicle in a market. Specifically, the information corresponding to the destination is usually stored in the non-volatile memory in an inspection step during the manufacturing of the vehicle. The inspection is carried out before shipping the vehicle out from a manufacturing plant. The information corresponding to the destination is written in the non-volatile memory by an external tool, which is connectable with the electronic control apparatus.
As another example, an electronic control apparatus may determine an abnormality occurrence based on information acquired from various on-board sensors. When an abnormality occurs to the vehicle, the electronic control apparatus stores abnormality information related to the abnormality in the memory. That is, when an abnormality occurs to an on-board sensor, diagnostic trouble code (DTC) related to the abnormality is stored in the non-volatile memory. A service man in a dealer facility or in a manufacturing plant can read out the DTC from the electronic control apparatus using an external tool, and repairs the vehicle or replaces a vehicle component based on the DTC that is read out from the vehicle as disclosed in JP 2009-059334 A (corresponding to US 2009/0037044 A1).
For example, when a mistake is made in an inspection step during a vehicle manufacturing process, the electronic control apparatus may mistakenly store DTC related to the mistake as a permanent diagnostic trouble code (PDTC) in a specified region of the memory in a non-volatile manner. That is, the PDTC may be mistakenly stored in the non-volatile memory before the shipment of the vehicle from the manufacturing plant.
Suppose that the vehicle is shipped out from the manufacturing plant with the PDTC stored in the non-volatile memory. The PDTC may indicate a mistake made by a worker in the manufacturing plant during the inspection step of the vehicle. After the vehicle is shipped out, when the destination of the vehicle is changed, DTC indicating the destination change is stored in the non-volatile memory as PDTC. After storing the information related to the destination change as the PDTC, the PDTC related to the mistake made by the manufacturing plant worker during the inspection step cannot be deleted from the memory because the PDTC related to the mistake is stored before the PDTC related to the destination change. That is, a deletion of mistakenly stored PDTC from the non-volatile memory becomes difficult. Thus, when the service man in the dealer facility or in the manufacturing plant reads out the PDTC using the external tool, the mistakenly stored PDTC is also read out from the non-volatile memory. As a result, even when there is no abnormality occurrence after the vehicle is shipped out from the manufacturing plant, the external tool may determine an abnormality occurrence based on the readout PDTC. Further, similar situation may happen when changing the ECU in the dealer facility after selling the vehicle to a client.